Iron

Ironisaubiquitouselementrequiredby virtually all cells for normal growth and metabolism. Rapidly growing and differentiating cellshaveparticularly high ironrequirements.¹Since preterm and term human infants have high growth rates (on a per-weight basis), it is not surprising that these infants also have high iron needs. Term infants typically acquire adequate iron stores during the last trimester of gestation, but preterm infants are relatively compromised in this respect.²This fact, combined with their higher postnatal growth rates in the first year, renders preterminfants at higher risk than their term counterparts for iron deficiency and iron-deficiency anemia.^{3, 4}This increased risk could theoretically be avoidedby administering large doses of iron to the preterminfant, were it not for the concern of iron toxicity; iron plays an important catalytic role in the Fenton reaction, which creates radical oxygen species that peroxidate the lipids in cell membranes. The concern is relevant particularly in the premature infant whose plasma total iron-binding capacity (TIBC) is lowand whose antioxidant defense system is immature.^{5, 6}Thus, ironcan be considereda highly necessaryelementwith a narrowtherapeutic window where both deficiency and overload contribute to significant morbidity. Iron balance in the fetus and neonate Iron is classically seen as an integral part of the hemoglobin molecule, and iron deficiency is thus frequently assumed to be synonymous with anemia.